Rotary expansible drill bits



Nov- 8, 1966 A, w. KAMMERER 3,283,834

ROTARY EXPANSIBLE DRILL BITS lol I N VE NTOR. Heal/E@ W K @n4/145,95@

2 Sheets-$heet l rra EY Nov. 8, 1966 A. w. KAMMr-:RER 3,283,834

ROTARY EXPANSIBLE DRILL BITS Filed Feb. lO, 1964 2 Sheets-Sheet a UnitedStates Patent O 3,283,834 RTARY EXPANSIBLE DRILL BITS Archer W.Kammerer, Fullerton, Calif., assigner of onefifth to Archer W. Kammerer,Jr., Houston, Tex., and one-fifth to .lean K. Lamphere, Fullerton,Calif.

Filed Feb. 10, 1964, Ser. No. 343,640 10 Claims. (Cl. 175-267) Thepresent invention relates to drill bits for use in well bores, and moreparticularly to rotary drill bits through which iiuid can be ejectedinto the well bores.

An object of the invention is to provide an improved drill bit, such asan expansible rotary drill bit, adapted to perform a drilling operationin a well bore, which is capable of discharging fluid predominantlylaterally -against the wall of the well bore in a relatively simple buthighly effective manner, for the purpose of conditioning the wall of thewell bore, or for discharging cementitious material into the well boreagainst its wall, the discharging fluid also having the purpose ofiiushing the cuttings produced by the bit from its drilling region inthe well bore.

This invention possesses many other advantages, and has other objectswhich may be more clearly apparent from a consideration of a form inwhich it may be ernbodied. This form is shown in the drawingsaccompanying and forming part of the present specification. It will nowbe described in detail, for the purpose of illustrating the .generalprinciples of the invention; but it is to be understood that suchdetailed description is not to be taken in a limiting sense, since thescope of the invention is best delined by the appended claims.

Referring to the drawings:

FIGURE l is a longitudinal section, taken along the line 1 1 in FIG. 3,through a drill bit disposed in -a well casing, with its parts in theirinitial position for moving the drill Ibit in the well bore;

FIG. 2 is an enlarged side elevational view of the lower portion of thedrill bit disclosed in FIG. l, with the main portion of the cuttersremoved therefrom;

FIG. 3 is a cross-section taken along the line 3-3 on FIG. l;

FIG. 4 is a view similar to FIG. l illustrating the drill bit with itscutters expanded outwardly;

FIG. 5 is a view similar to FIG. 4, but on a reduced scale, illustratingthe lateral discharge of iiuid from the well bit apparatus and againstthe wall of a well bore.

The drill bit A illustrated in the drawings is of the expansible typeand is specically designed for cutting or milling away a portion ofcasing B, or similar conduit string, disposed in a well bore C along adesired length. Following milling away of the desired length of casing,fluid can be discharged from the drill bit predominantly laterallyagainst the wall of the exposed well bore D (FIG. 5) to accomplishseveral purposes, such as the removal of a mud cake therefrom, thehydraulic enlarging of the diameter of the well bore, the depositing ofcementitious material in the well bore, or a combination of theseseveral operations. The apparatus A is secured to the lower end of astring of drill pipe E (see FIG. 5) that extends to the top of the wellbore, and by means of which the apparatus is lowered through the casingB to a location therein at which the casing milling operation is tocommence, and where other operations are also to be performed withoutremoving the drill bit from the well casing.

The expansible rotary drill bit includes an upper mandrel having anupper pin 11 -threadedly connected to the lower end of the string ofdrill pipe E. This mandrel includes an upper kelly or drill stem member12 slidably splined to the main body 13 of the bit which has a lower iceguide portion 13a. The exterior of the lower portion 14 of the kelly isnon-circular in shape, being telescopically received in a companionnon-circular socket 15 formed in the main bit body 13. Specifically, thekelly exterior and `the socket 1S may be hexagonally shaped to enablethe kelly 12 to be moved longitudinally with respect to the body 13,while still being capable of transmitting rotary motion to the body.

The mandrel 10 has a limited range of longitudinal movement within thebody, its relative downward movement being determined by engagement ofthe lower end 16 of the kelly with an inwardly directed body shoulder17, and its upward movement being limited by engagement of an externalshoulder or piston portion 18 of the kelly with a cylinder head 19secured to the body against longitudinal movement with respect thereto.The upper end of the head has a flange 20 engaging an upwardly facingbody shoulder 21, the liange being prevented from moving upwardly of thebody by a split snap retainer ring 22 fitting in a body groove 23 andoverlying the flange 20. An annular guide 24 is releasably secured tothe body 13 by a split snap ring 25 above the retainer rings 22.

The body has a plurality of expansible parts mounted on it. Theseinclude cutter supporting members 26 pivotally mounted in body slots 27on binge pins 28 suitably secured to the body to prevent their losstherefrom. Each cutter supporting member 26 depends from the hinge pin28 and carries a drag or milling cutter structure 29 at its lower end,which may be suitably welded, or otherwise attached, to the supportingmember 26.

The cutter supporting members 26 and the cutter structures 29 tend tooccupy a retracted position substantially entirely within the confinesof the main body 13 of the bit. These cutter supporting members and thecutter structures are expandible outwardly to sever the casing B andmill it away by operating upon the upper end F of the casing therebelow.To accomplish the expansion, each cutter supporting member has aninclined expander surface 30 on its inner portion below the hinge pin 284that tapers in a downward and inward direction. Each expander surfaceterminates in a lock surface 31 formed on a lock portion 32 of t-hecutter supporting member 26. The outward expansion is accomplished byproducing relative longitudinal movement between the mandrel v10 and thebit body 13, which will produce relative longitudinal movement betweenthe cutter supporting members 26 and the tubular member 33 of themandrel 10.

The tubular member 33 includes a lower portion 34 slidably mountedwithin a guide bushing 35 slidable in a bridge 36 secured to the bodyand extending; across the body slots 27. This guide bushing 35 -isdisposed below the lock portions 32 of the cutter supporting members 26.The tubular member 33 extends downwardly of the guide bushing 35 and isadapted to discharge liluid axially, of the drill bit apparatus towardand against diverter or deector surfaces formed in the body at the lowerportion of each of the body slots 27, each of these deector surfacesbeing inclined from the body axis in a downward and outward direction.Each deliector surface 100 commences at an upper position substantiallycoaxial of the bit body 13 and the mandrel 10, and inclnes in a downwardand outward direction at a substantial angle, which, for example, may beabout 45 degrees to the axis ofthe apparatus. The fluid discharging fromthe mandrel 10 will strike all of the lower deiiector surfaces 100 andwill be directed predominantly laterally through the lower ends 101 ofthe slots or openings toward the wall of the well casing B or wall ofthe well bore D. Preferably, `the deliector surfaces 100 are disposedbelow the lower ends of the cutters 29 so that the deflected or divertedfluid is not obstructed in being caused to impinge upon the Wall ofthewell bore.

Located initially substantially above the guide bushing 35 and below thehinge pins 28, and in cutter member recesses 37, is a mandrel lock andexpander 38 which has outer surfaces 39 adapted to engage the expandersurfaces 30 and lock surfaces 31. The lock and expander 38 may be formedintegrally with the tubular member 33, the upper end of the latter beingpiloted within a socket 40 -formed on the lower portion 14 of the kelly12. An enlarged boss 41 on the tubular member 33 engages a downwardly-lacing shoulder 42 of the kelly, the tubular member being held againstthis shoulder by a suitable split retainer or lock ring 43 snapped intoan internal groove 44 encompassing the kelly socket and engaging thelower end of the tubular member boss 41.

Drilling mud or other fluid can pass down through the central passage 45in the kelly or drill stem 12 and into the central passage 46 thatextends completely through the tubular member 33, this fluid or flue-ntmaterial passing through a nozzle 1015 of suitable size secured withinthe lower end of the tubular member passage 46, and thence directlydownwardly, strik-ing the dellector surfaces 100 and then passinglaterally outwardly through the lower portions 101 of the body slots 27in a direction pred'o-minnantly aga-inst the wall of the well casing Bor well bore D. In fact, the fluid might strike such wall substanttiallynormal thereto. Leakage of fluid `around the exterior of the tubularmember 33 is prevented by a suitable side seal ring 47 mounted in thekelly and engaging the exteri-or of the boss 41.

Assuming .the body 13 of the tool to be elevated relatively along thetubular mandrel 10, the inclined expander surface-s 30 of the cuttersupporting members 26 will be shifted upwardly along the lock andexpander portion 3S of the tubular member 33. During such upwardshifting, the cutter supporting members 26 and the cutter structure-s 29carried thereby will be pivoted about the hinge pins 28 and urged i-n anoutward direction. The upward movement of the body 13 with respect tothe tubular mandrel can continue until the cutter structures 29 havebeen shifted outwardly to their fullest extent, as determined byengagement of stop shoulders 49` on the cutter supporting members 26with companion shoulders 50 tor-med in the body on opposite sides of thebody slots 27. When such engagement occurs, the lower end 16 off thekelly portion 12 of the tubular mandrel will engage the body shoulder17, and the lock and expander 38 on the tubular member 33 will bedisposed behind and in engagement with the lock portions 32 on thecutter supporting members 26 (FIGS. 4 and 5). At the same time, it willbe noted that the elevation of the body 13 has brought the deflectorsurfaces 100 at the lower portions of the body slots 27 closer to thenozzle or discharge outlet 105 of the tubular mandrel portion 33, suchthat any lluid discharging trom the latter will still possesssubstantial and high velocity when striking the adjacent incl-ineddeector surfaces 100.

Relative longitudinal movement between the tubular mandrel and the body13 of .the tool is accomplished hydraulically in the specic form ofapparatus disclosed in the drawings. The piston or enlarged portion 18of .the drill stern 12 is received within .a counterbore 51 in the upperportion of the body of the tool. This upper portion actually constitutesa cylinder 52 having a cylinder wall `53 extending trom a lower shoulder54 defining the bottom ol the counterbore 51 to the cylinder head 19.

A conned cylinder space 55 is formed between the pistion portion 18 ofthe kelly, fthe periphery of the kelly above the piston, and thecylinder 52. A suitable packing or side seal ring 56 may be mounted onthe piston por- 'tion 118, which is adapted to slidably seal against thecylindrical wall 53 of the cylinder `52. Fluid is thereby prevented rompassing in a downward direction between the piston and cylinder.Similarly, lluid is prevented from passing in an upward direct-ion outof the annular cylinder space 55- by an inner side seal ring 58 carriedby the cylinder head 19 and slidably `and sealingly engaging theperiphery or the kelly 12 above the piston 1.8, and also by an outerside seal ring 60 on the head 19 sealingly engaging lthe cylinder wall53.

Fluid under pressure in the string of drill pipe E and in the tubularmandrel passage 45 can be fed into the cylinder space 55 through one ormore side ports 62 establishing communication between the centralpas-sage 45 through the kelly 12 and .the cylinder space. Such lluidunder pressure is developed, in the form of invention disclosed inthedrawings, by virtue of the fact that the area through the lower nozzle105 is substantially less than the area of the passage 45 through thekelly portion of the mandrel, or because of the fact that the passage 46through the tubular member 33 of the mandrel is of a restricted diameteras compared to the passage 45. As a result, the pumping ot drilling mud,or other fluid, at an adequate rate through the .apparatus results inthe building up of a back pressure of fluid in the passage 45, wh-ichpressure will then be imposed on the lluid in the cylinder space 55,such fluid under pressure acting upon the cylinder head 19 .to urge thebody 13 of the tool in an upward direction with respect .to the tubularmandrel 10 and secure outward expansion of the cutter supporting members26 and cutter structures 29 to their fullest extent, as above described.During such upward movement of the body 13 along the mandrel 10, thedellector suraces at the lower ends of the slots 27 are, as has beendescribed above, brought closer to the 4discharge end of the nozzle 105or tubular member 33.

IIn the use of the rotary drill bit A, it is run in the well casing withthe cutter supporting members 26 and the cutter structures 29 in theirinitial retracted positions, such as disclosed in FIG. l. When the drillbit has been lowered to the desired point in the well casing `at whichthe latter is :to be severed, the pump-s (not shown) at the top of thewell bore are started to pump liuid at a sucient rate through the dril'lpipe and into the mandrel passages 45, 46, and through its lower nozzle105, building up a back pressure in the kelly passage 45, ports 62 andcylinder space 55, which pressure acts upon the cylinder head 19 to urgethe body 13, the cutter supporting members `26 and the cutter structures29 in an upward direction with respect to .the mandrel 10. During suchupward movement, the expander surfaces 30 are brought to bear againstthe lock and expander portion 38 of the mandrel, the cutter structuresbeing urged in an outward direction against the wall of the well casing.The drill pipe E land the drill bit A are rotated at the proper speedwhile fluid is being pumped through the apparatus, the outer edges orthe cutters 29, acting upon the wall of the casing and gradually millingit away. During this operation, the drill bit is retained insubstantially the sam-e longitudinal posit-ion in the well casing. Asthe casing is cut away, the hydraulic torce acting upon the body 13raises it and the cutter slipporting members 26 .and cutter structures29 to a further extent until the outer edges of the cutters havecompletely severed the casing. Thereafter, rotation of the drill pipe Eand the drill bit continues, so that the outer reaming portions of thecutters 29 continue to cut away the casing and dig into the formationuntil the cutters have been fully expanded outwardly to their maximumextent as determined by engagement of the stop shoulders 49, 50 and thelower end 16 of the kelly portion 12 of ythe mandrel with the bodyshoulders 17. Wirth the parts in this position, the lock port-ion 32 ofeach cutter supporting member 26 will bear against the lock and expanderportion 38 of the tubular member 33 to preclude inadvertent partialretraction of the cutter structures 29 from the-ir fully expandedposition (FIG. 4).

Downweight in the proper amount is now imposed on the string of drillpipe, this downweght being transmitted through the kelly 12 to the bodyshoulder 17 and from the body 13 to the stop shoulders 50, 49 directlyto the cutter supporting members 26 and the cutter structures 29, urgingthe latter against the upwardly facing severed end F of the well casing.The imposition of the proper downweight or drilling weight on theapparatus and its rotation at the proper speed will cause the cutters 29to effect a cutting action upon the severed end F of the casing and millthe latter away in a downward direction. During such milling action,drilling fluid is being pumped down through the drill pipe E and mandrel10, discharging from the lower nozzle 105 against the deflector surfaces100, which causes the fluid to be directed predominantly laterallytoward the wall of the well casing B, the fluid then proceeding upwardlyto pass around the cutters 29 and clean them of cuttings, and to carrythe cuttings upwardly around the drill bit A and the drill pipe E to thetop of the hole (FIG. 4).

After the desired length of casing has been milled away, which, forexample, may be of a length of about 20 feet to 40 feet, the downweightimposed on the apparatus A is discontinued. A subsequent operation cannow be performed in the well bore without removing the apparatus fromthe latter. If it is desired to` enlarge the diameter of the well bore Dproduced by the expanded cutters, circulating fluid is pumped downthrough the drill pipe E and through the apparatus A, discharging fromthe lower nozzle S against the deflector surfaces 100 at the lower endof the body slots, the fluid then being caused to move laterally at asubstantial angle, which may be approximately 90 degrees, against thewall of the exposed well bore D. The drill string and apparatusconnected thereto are rotated at the desired speed during such pumpingoperation so that the diverted or deflected fluid streams are caused tocover the entire circumference of the well bore D. While the rotationand pumping of fluid operations are continued, the drill pipe E and thedrill bit A are gradually elevated, beginning from the lower end of theexposed well bore D, so that the fluid deflected by the inclined lowerslot walls 100` is caused to impinge upon the desired length of the wallof the well bore above the lower shoulder F, G provided by the lower endof the severed well casing and the enlarged well bore itself. Theapparatus A can be elevated along the entire length of the well bore D,if desired, during its rotation to insure the full coverage of thedeflected fluid streams of the entire surface of the exposed well bore.The apparatus can be raised and lowered as often as required to insurethe accomplishment of the hole enlarging operation.

A hydraulic hole enlarging operation can occur in the manner describedabove. Such enlarging operation usually results in the removal of themud cake from the wall of the well bore D, so that cementitious materialsubsequently deposited in the well bore along its exposed wall willadhere 'firmly to the latter.

Fluid of the required type and at the proper velocity can be pumpedthrough the apparatus A, while the latter is being rotated and elevatedalong the well bore, merely to condition the well bore D and remove themud cake from the wall of the latter without substantially enlarging thewell bore, if desired, assurance being had that the diverted streams offluid will impinge upon the exposed well bore in a highly effectivemanner, the mud cake, and other undesirable elements, in the well borebeing flushed upwardly around the drill pipe E to the top of the hole C.

The apparatus A is usable for depositing cement in the well bore alongits exposed portion D, to form a cement plug therewithin, withoutremoving it from the hole after the section of casing has beendisintegrated. The pumping of cement slurry downwardly through the drillpipe E and through the mandrel 10 will result in the cement slurry, orother cementitious material, discharging from the nozzle 105 at a highvelocity, striking the defiector surfaces 100 at the lower ends of theslots 27 and being directed predominantly against the wall of theexposed well bore. The drill pipe and drill bit can be rotated andgradually elevated while the cement slurry is being discharged from theapparatus A, the point of discharge commencing at the lower end G of theexposed bore and the apparatus `elevated while its rotation continues toinsure the direct impinging of the cement slurry against the wall of thewell bore and its intimate contact therewith. The cement slurrydischarges directly against the wall without interference from thecutters 29, since the deilector or diverter surfaces causes the slurryto discharge through the slots 27 below the lower ends of the cutters.The cement slurry will Slough downwardly and form a plug in the enlargedwell bore D.

When the desired quantity of cement slurry has been ejected into theexposed well bore D and to the desired height, the apparatus can beelevated above the upper end of the cement. Flushing fluid is pumpeddownwardly through the drill pipe E to wash the excess cement from thedrill pipe and the drill bit A, such cement slurry being carriedupwardly around the rotary drill bit and the drill pipe to the top ofthe well bore C.

The pumping of fluids through the drill pipe and apparatus can nowcease, which will discontinue the hydraulic force holding the body 13 ofthe tool elevated along the mandrel 10 and the cutters 29 in theiroutwardly expanded position. The body of the tool .will then dropdownwardly along the mandrel back to the position illustrated in FIG. l,allowing the cutters 29 to move inwardly to their fully retractedposition, whereupon the drill string E and apparatus A can be elevatedthrough the well casing B above the exposed well bore D and removedentirely from the latter at the top of the hole C.

It is, accordingly, apparent that the apparatus A is capable ofperforming several operations in the well bore with a single round trip,The apparatus is useful in first performing a milling action to exposethe well bore D along a desired length, and without removing theapparatus from the well bore. The exposed portion of the latter can beenlarged hydraulically, the mud cake removed therefrom, or cement slurrydischarged from the apparatus into the well bore, or any combination ofthese operations can be performed. The fluid emanating from the nozzlestrikes the defleetor surfaces 100 at the lower end of' the slots toinsure adirect and intimate contact of the fluent mass against the wallof the well bore, this action resulting from the simple expedient ofproviding the inclined deilector surfaces on the body 13 of the drillbit at the lower portion of the body slots. Preferably, the deflectorsurfaces are angled to such an extent that the fluid deflected therefromstrikes the wall of the well bore at substantially 90 degrees thereto,although the fluid streams can strike the wall of the well bore D in adownward and outward direction, but primarily directly against the wallof the well bore.

I claim:

1. In rotary drill bit apparatus to be lowered in a bore hole on atubular drill string: a body having an opening through its exterior,said body at the lower portion of said opening having a deflectorsurface inclined downwardly and laterally outwardly; expandible cuttermeans on said body; the lower end of said cutter means being locatedsubstantially above said deilector surface to provide a substantialunobstructed longitudinal space through the lower portion of saidopening between said lower end of said cutter means and said deilectorsurface; a mandrel movable longitudinally in said body and having apassage adapted to receive fluid from the drill string, the lower end ofsaid passage terminating above said deilector surface, whereby fluiddischarged from said lower end strikes said dellector surface and isdeflected thereby laterally outwardly through said unobstructedlongitudinal space of said opening against the wall of the bore hole;said dellector surface being angled to a degree causing the fluiddischarged thereagainst to 7 strike the wall of the bore hole `atsubstantially 90 degrees thereto without directly striking said cuttermeans; and coengageable means on said mandrel and cutter means forexpanding said cutter means in response to relative longitudinalmovement between said body and mandrel.

2. In rotary drill bit apparatus to be lowered in a bore hole on atubular drill string: a body having an opening through its exterior,said body at the lower portion of said opening having a deilectorsurface inclined downwardly and laterally outwardly; expandible cuttermeans on Said body; the lower end of said cutter means being locatedsubstantially above said deector surface to provide a substantialunobstructed longitudinal space through the lower portion of saidopening between said lower end of said cutter means and said deflectorsurface; means for expanding said cutter means laterally outwardly ofsaid body, comprising a mandrel movable longitudinally in said body andhaving a passage adapted to receive fluid from the drill string, thelower end of said passage terminating above and adjacent to said deectorsurface, whereby uid discharged from said lower end strikes saiddetlector surface and is deflected thereby laterally outwardly throughsaid unobstructed longitudinal space of said opening against the wall ofthe bore hole; said deector surface being angled to a degree causing theuid discharge thereagainst to strike the wall of the bore hole atsubstantially 90 degrees thereto without directly striking said cuttermeans.

3. In rotary drill bit apparatus to be lowered in a bore hole on atubular drill string: a body having an opening through its exterior,said body at the lower portion of said opening having a deflectorsurface inclined downwardly and laterally outwardly; expandible cuttermeans on said body; the lower end of said cutter means being locatedsubstantially above said deflector surface to provide a substantialunobstructed longitudinal space through the lower portion if saidopening between said lower end of said cutter means and said deflectorsurface; means for expanding said cutter means laterally outwardly ofsaid body; passage means in said body adapted to receive uid from thedrill string and having a lower end terminating above and adjacent tosaid decctor surface, whereby fluid discharged from said lower endstrikes said deflector surface and is deected thereby laterallyoutwardly through said unobstructed longitudinal space of said openingagainst the wall of the bore hole; said deflector surface being angledto a degree causing the fluid discharged thereagainst to strike the wallof the bore hole at `substantially 9() degrees thereto without directlystriking said cutter means.

4. In rotary drill bit apparatus to be lowered in a bore hole on atubular drill string: a body having an opening through its exterior,said body at the lower portion of said opening having a deilectorsurface inclined downwardly and laterally outwardly; cutter means onsaid body; the lower end of said cutter means being locatedsubstantially above said deflector surface to provide a substantialunobstructed longitudinal space through the lower portion of saidopening between said lower end of said cutter means and said deectorsurface; passage means in said body adapted to receive fluid from thedrill string and having a lower end terminating above and adjacent to`said detlector surface, whereby lluid discharged from said lower endstrikes said deflector surface and is deected thereby laterallyoutwardly through said unobstructed longitudinal space of said openingagainst the wall of the bore hole; said deflector surface being angledto a degree causing the lluid discharged thereagainst to strike the wallof the bore hole at substantially 90 degrees thereto without directlystriking said cutter means.

5. In rotary drill bit apparatus adapted to be lowered in a bore hole ona tubular drill string: a body having a plurality of circumferentiallyspaced slots, said body at the lower portion of each slot having adeflector surface inclined downwardly and laterally outwardlysubstantially from the axis of said body; expandible cutter means onsaid body in said slots; the lower ends of said cutter means beinglocated substantially above said deflector surfaces to providesubstantial unobstructed longitudinal spaces through the lower portionsof said slots between said lower ends of said cutter means and saiddeflector surfaces; a mandrel movable longitudinally in said body andhaving a central passage coaxial of said body adapted to receive fluidfrom the drill string, the lower end of said passage terminating abovethe inner portions of said deflector surfaces at the body axis, wherebytiuid discharged from said lower end strikes said deflector surfaces andis deflected outwardly through said unobstructed longitudinal spaces ofsaid slots against the wall of the bore hole; said defiector surfacesbeing angled to a degree causing the uid discharged thereagainst tostrike the wall of the bore hole at substantially 90 degrees theretowithout directly striking said cutter means; and coengageable means onsaid mandrel and cutter means for expanding said cutter means inresponse to relative longitudinal movement between said body andmandrel.

6. In rotary drill bit apparatus adapted to be lowered in a bore hole ona tubular drill string: a body having a plurality of circumferentiallyspaced slots, said body at the lower portion of each slot having adetiector surface inclined downwardly and laterally outwardlysubstantially from the axis of said body; expandible cutter means onsaid body in said slots; the lower ends of said cutter means beinglocated substantially above said deector surfaces to provide substantialunobstructed longitudinal spaces through the lower portions of saidslots between said lower ends of said cutter means and said deflectorsurfaces; means for expanding said cutter means laterally outwardly ofsaid body, comprising a mandrel movable longitudinally in said body andhaving a central passage coaxial of said body adapted to receive fluidfrom the drill string, the lower end of said passage terminating aboveand adjacent to the inner portions of said deector surfaces at the bodyaxis, whereby fluid discharged from said lower end strikes saiddeflector surfaces and is deflected outwardly through said unobstructedlongitudinal spaces of said slots against the wall of the bore hole;said deflector surfaces being angled to a degree causing the fluiddischarged thereagainst to strike the wall of the bore hole atsubstantially 90 degrees thereto without directly striking said cuttermeans.

7. In rotary drill bit apparatus adapted to be lowered in a bore hole ona tubular drill string: a body having a plurality of circumferentiallyspaced slots, said body at the lower portion of each slot having adeilector surface inclined downwardly and laterally outwardlysubstantially from the axis of said body; expandible cutter means onsaid body in said slots; the lower ends of said cutter means beinglocated substantially above said deflector surfaces to providesubstantial unobstructed longitudinal spaces through the lower portionsof said slots between said lower ends of said cutter means and saiddeflector surfaces; means for expanding said cutter means laterallyoutwardly of said body; passage means in said body coaxial thereof andadapted to receive fluid from the drill string and having a lower endterminating above and adjacent to the inner portions of said deflectorsurfaces at the body axis, whereby fluid discharged from said lower endstrikes said deflector surfaces and is deflected outwardly through saidunobstructed longitudinal spaces of said slots against the wall of thebore hole; said deflector surfaces being angled to a degree causing thefluid discharged thereagainst to strike the wall of the bore hole atsubstantially degrees thereto without directly striking said cuttermeans.

8. In rotary drill bit apparatus to be lowered in a bore hole on atubular drill string: a body having a plurality of circumferentiallyspaced openings, said body at the lower portion of each opening having adeiiector surface in- Cliued downwardly and laterally outwardlysubstantially from the axis of said body; cutter means on said body; thelower ends of said cutter means being located substantially above saiddeilector surfaces to provide substantial unobstructed longitudinalspaces through the lower portions of said openings between said lowerends of said cutter means and said deflector surfaces; passage means insaid body coaxial thereof and adapted to receive fluid from the drillstring and having a lower end terminating above and adjacent to theinner portions of said deflector surfaces at the body axis, wherebylluid discharged from said lower end strikes said deflector surfaces andis deflected outwardly through said unobstructed longitudinal spaces ofsaid openings against the wall of the bore hole; said detiector surfacesbeing angled to a degree causing the luid discharged thereagainst tostrike the wall of the bore hole at substantially 90 degrees theretowithout directly striking said cutter means.

9. In a rotary drill bit adapted to be lowered in a bore hole on atubular string: a body having a plurality of circumferentially spacedslots; expandible cutter means on said body in said slots; said body atthe lower portion of each slot having a deflector surface below thelower end of the cutter in said slot inclined downwardly and laterallyoutwardly substantially from the axis of said body; the lower ends ofsaid cutter means being located substantially above said deflectorsurfaces to provide substantial unobstructed longitudinal spaces throughthe lower portions of said slots between said lower ends of said cuttermeans and said deflector surfaces; a mandrel movable longitudinally insaid body and having a central passage coaxial of said body adapted toreceive luid from the drill string, the lower end of said passageterminating above the inner portions of said defiector surfaces at thebody axis, whereby uid discharged from said lower end strikes saiddelector surfaces and is deflected outwardly through said unobstructedlongitudinal spaces of said slots and below said cutter means againstthe wall of the bore hole; said deector surfaces being angled to adegree causing the fluid discharged thereagainst to strike the wall ofthe bore hole at substantially degrees thereto without directly strikingsaid cutter means; and coengageable means on said mandrel and cuttermeans for expanding said cutter means in response to relativelongitudinal movement between said body and mandrel.

l0. In rotary drill bit apparatus to be lowered in a bore hole on atubular drill string: a body having a plurality of circumferentiallyspaced openings; cutter means on said body; said body at the lowerportion of each opening and below said cutter means having a deflectorsurface inclined downwardly and laterally outwardly substantially fromthe axis of said body; the lower ends of said cutter means being locatedsubstantially above said deiiector surfaces to provide substantialunobstructed longitudinal spaces through the lower portions of saidopenings between said lower ends of lsaid cutter means and saiddellector surfaces; passage means in said body adapted to receive fluidfrom the drill string and having a lower end terminating above andadjacent to the inner portions of said deflector surfaces at the bodyaxis, whereby fluid discharged from said lower end strikes saiddefiector surfaces and is deliected outwardly through said unobstructedlongitudinal spaces of said openings below said cutter means and againstthe wall of the bore hole; said deilector surfaces being angled to adegree causing the fluid discharged thereagain-st to strike the wall ofthe bore hole at substantially 90 degrees thereto without directlystriking said cutter means.

References Cited by the Examiner UNITED STATES PATENTS 2,545,036 3/1951Kammerer 175-271 2,754,089 7/1956 Kammerer 175-268 2,758,819 8/ 1956Kammerer 175-267 3,126,065 3/ 1964 Chadderdon 175-269 CHARLES E.OCONNELL, Primary Examiner.

D. H. BROWN, Assistant Examiner.

1. IN ROTARY DRILL BIT APPARATUS TO BE LOWERED IN A BORE HOLE ON ATUBULAR DRILL STRING: A BODY HAVING AN OPENING THROUGH ITS EXTERIOR,SAID BODY AT THE LOWER PORTION OF SAID OPENING HAVING A DEFLECTORSURFACE INCLINED DOWNWARDLY AND LATERALLY OUTWARDLY; EXPANDIBLE CUTTERMEANS ON SAID BODY; THE LOWER END OF SAID CUTTER MEANS BEING LOCATEDSUBSTANTIALLY ABOVE SAID DEFLECTOR SURFACE TO PROVIDE A SUBSTANTIALUNOBSTRUCTED LONGITUDINAL SPACE THROUGH THE LOWER PORTION OF SAIDOPENING BETWEEN SAID LOWER END OF SAID CUTTER MEANS AND SAID DEFLECTORSURFACE; A MANDREL MOVABLE LONGITUDINALLY IN SAID BODY AND HAVING APASSAGE ADAPTED TO RECEIVE FLUID FROM THE DRILL STRING, THE LOWER END OFSAID PASSAGE TERMINATING ABOVE SAID DEFLECTOR SURFACE, WHEREBY FLUIDDISCHARGED FROM SAID LOWER END STRIKES SAID DEFLECTOR SURFACE AND ISDEFLECTED THEREBY LATERALLY OUTWARDLY THROUGH SAID UNOBSTRUCTEDLONGITUDINAL SPACE OF SAID OPENING AGAINST THE WALL OF THE BORE HOLE;SAID DEFLECTOR SURFACE BEING ANGLED TO A DEGREE CAUSING THE FLUIDDISCHARGED THEREAGAINST TO STRIKE THE WALL OF THE BORE HOLE ATSUBSTANTIALLY 90 DEGREES THERETO WITHOUT DIRECTLY STRIKING SAID CUTTERMEANS; AND COENGAGEABLE MEANS ON SAID MANDREL AND CUTTER MEANS FOREXPANDING SAID CUTTER MEANS IN RESPONSE TO RELATIVE LONGITUDINALMOVEMENT BETWEEN SAID BODY AND MANDREL.